The surface of Enceladus, one of Saturn's moons.
(Photo: NASA/JPL/Space Science Institute )

March 13, 2006Thanks to a discovery on the surface of Enceladus, one of Saturn's moons, the scientific community is buzzing about an age-old question: Is there life on other planets?

Images taken by the orbiting Cassini spacecraft reveal water erupting from geysers on Enceladus's surface. These findings were published on Friday in the journal Science. The presence of water suggests that it might be possible for some form of life to exist there.

"We realize that this is a radical conclusion," said Carolyn Porco, leader of the Cassini imaging team at the Space Science Institute in Colorado. "However, if we are right, we have significantly broadened the diversity of solar system environments where we might possibly have conditions suitable for living organisms."

The Cassini spacecraft first went into orbit around Saturn in 2004. It was part of a recent effort by the National Aeronautics and Space Administration (NASA) and the European Space Agency to study Saturn and its 33 moons. Last July, scientists first noticed that Enceladus had a smooth surface. As the Cassini spacecraft moved closer, it found a plumesimilar to geysers, like the ones at Yellowstone National Parkspitting out water vapor and tiny particles. Experts believe the likely source of the plumes are pockets of water near the moon's surface.

Potential Life

The discovery of liquid water prompted many scientists to discuss the possibility that Enceladus has living organisms. Most scientists agree that, to sustain life, a region has to have three important thingswater, heat, and carbon-based molecules. It is clear that Enceladus has water, but what about the other ingredients?

Simple carbon-based life forms have already been discovered on this moon's surface. It appears that Enceladus may have heat too. The Cassini spacecraft focused on the moon's south polea region scientists believe is unusually "warm." While the average temperature of Enceladus is minus 316 degrees Fahrenheit, its southern hemisphere was minus 261 degrees. Scientists think this "hot spot" could be a result of the gravitational pull on Enceladus by Saturn (the friction from the pull could cause heat).

Minus 261 degrees is frigid by Earth's standards. But if there is life on Enceladus, it will likely be primitive organisms that can survive in this extreme temperature.

"I think the best you can say is there is potential [for life]," said Candy Hansen, of NASA's Jet Propulsion Laboratory. "We have liquid water probably, and it is in contact with rocks, so there are minerals. And there's energy, but we haven't detected life."